METHODS OF ROTOGRAVURE PRINTING FOR OBTAINING OPTICALLY CHANGING SIGNS OF PROTECTION Russian patent published in 2017 - IPC B41M3/14 

FIELD: printing industry.

SUBSTANCE: invention relates to the field of optical changing elements of protection, containing an area based on the once cured ink containing cholesteric liquid crystal polymer, wherein specified area has at least two, preferably at least three, drawings, characterised by, at least under a one angle of observation, different in parameter of colour indexes of colour space CIE (1976) and/or different location of stripes of selective reflection, for protection of protected documents from forgery and/or illegal play. In particular, the invention relates to methods for manufacturing these features. These methods include steps of: a) applying one cholesteric liquid crystal composition-predecessor to a substrate by method of rotogravure printing using the plate cylinder, with at least two, preferably at least three different engravings; b) heating of applied composition to bring the specified composition in cholesteric liquid crystal state, and c) curing composition with reception of area on the basis of momentary cured inks containing cholesteric liquid crystal polymer.

EFFECT: providing method to obtain optically changing sign of protection based on the cholesteric liquid crystal polymer by easy, economical, improved, predictable, repeatable and controllable way.

14 cl, 1 tbl, 1 dwg